Please bear (not a bear thread) until I get to the main question at the end.

I've been reloading for my Mosin Nagant. PPU makes 7.62mmx54R ammo with a bullet diameter of .312" which is ACTUALLY 7.92mm, that shoots just fine, so I stock up with 7.92 mm (.312") dia. bullets.

Now I have an SKS. I honestly don't think that I can reload for it as cheap as Tula steel cased ammo, but I want to be ready in case they decide to stop importing it or some nonsense.

The bullet in the Tula Ammo is designated 7.62 also. Ok, I know cartridge conventions are weird but both of these cartridges came from Russia/Soviet Union. The bullet actually measures .310" diameter or 7.65mm.

Wikipedia also defines the 7.62 x 54R as having a .312" dia. bullet which is actually 7.92mm.

Wikipedia also defines the 7.62 x 39 cartridge as having a .312" diameter bullet which is actually 7.92 mm.

Forget 7.62 as I know that is a designation for the '3 lin' .30 caliber class of cartridges.

But WHY do the Russians make .310" diameter bullets for a cartridge that's supposed to be .312"?

If I don't want to stock 2 different dia. bullets I guess I could slug the barrels and see what the actual groove diameters are.

It's probably moot because it seems that the sks takes lighter bullets in general Even so, the question is still there and the answer will probably be 'who knows?' unless some of you veteran loaders of Russian surplus rifles have some inside knowledge.

I think the 7.62 designation was the bore diameter,,not the groove diameter.
That was the common way of cartridge/caliber designation in Europe and the rest of the World though nothing that was set in stone of course..

The name doesn't mean anything. I could invent a new cartridge with a 6.8mm bullet and call it a "7.62 Smith" or some such because it is the 'nominal diameter' of something or other.

I'm going to be looking into this more because I don't think it's a matter of quality control, but of bullet selection. Note that both sizes of bullets are standard and sold here.

I did physically measure the 7.62 x 39 round and it is .310" The reloading bullets I use for the Mosin Nagant and Arisaka are .312", also suitable for loading .303 Endfields

As far as worn barrels and such go, slugging is the only way to determine what they are and I'm going to do it today, or very soon. Neither of the rifles appear to have been used heavily but that doesn't show in the barrel.

PS: I shot the new SKS yesterday with the Tula Ammo and shot just fine with the .310" bullets.

Both are military rifles and if produced in war time the barrels may or may not be even close to what they "are supposed to be". I have an MN with a groove diameter on .315", a Lee Enfield with a groove diameter of .318" both bigger than what "they're supposed to be". Slug your barrels and know for sure what your rifles barrel's are...

Per the Hornaday manual, the 7.62 x 39 mm has an official nominal groove diameter of 0.311 in. 7.62 x 54R mm has an official nominal groove diameter that tends to run 0.311-0.312 in. There is going to be some variation in nominal dimensions, they're supposed to vary on the plus-oversize- side. Given the original design date of the older round, tolerances would be more generous. But, ignoring that, the tolerance directive is to make the hole larger than nominal and whatever goes in the hole smaller.

I wouldn't worry about a difference of one one thousandth of an inch too much. Per Hornady, CIP standards list the Finnish 7.62 x 53R mm and Russian 7.62 x 54 R mm cartridges as interchangeable. The Finnish cartridge uses a 0.308 in bullet & bore, the Russian 0.312 in.

You also have to make allowances for the design intent and tactical doctrine that drove the development of the 7.62 x 39 mm cartridge and it's weapon systems. They were basically building a bullet hose to mop up what survived the massive artillery barrage and followup armored assault. Our standards of accuracy weren't part of the equation. Given those considerations, accuracy took a back seat to reliability under harsh conditions while being used by .....technologically challenged users.

To cover the IOWAWKT or SHTF possibilities I bought a Lee 303 RH/GC bullet mould. I own .308. .309, .310, .312, & .314 sizers. With a few other moulds I own, this covers 30 Luger, 32 ACP, 32-20, 7.62x23, 39, & 54, as well as 7.7 Jap, 303 Brit 7.65 Argentine & Belgium. I found a 124-5 grain semi spritzer w/GC that is great for 7.62 x 39.

Most Com-Block rifles are in .311ish, but the Finnish and Westinghouse made MN rifles and the 1985 Military Winchesters are all in .308 (as were the 303 British 1895's). The vast majority of these rifles were never intended for precision shooting! So if you got one that shoots well, don't fix it!

I'm thinking about loading lead in these rifles. I'll keep this in mind. I generally load down rifles, more fun to shoot that way. I'm not sure how far down I can go on the SKS and keep good function, but it doesn't bother me one bit to experiment around.

I load for a Ruger mini 30, I use Nosler 123g .310 dim. spritzer bullet over 23g of Hodgdon 4198 in a winchester case. It is accurate with 2 inch group at 50 yard with iron sights. The barrel on the mini 30 is not match grade but it does a good job for plinking and deer hunting.

I'm thinking about loading lead in these rifles. I'll keep this in mind. I generally load down rifles, more fun to shoot that way. I'm not sure how far down I can go on the SKS and keep good function, but it doesn't bother me one bit to experiment around.

Depending on the rifle, I have found best accuracy and 100 percent function of the semi's at 14,2 to 15.5 grains of 2400. Each one I have is different. Lots of variation in SKSs.

Now I have an SKS. I honestly don't think that I can reload for it as cheap as Tula steel cased ammo, but I want to be ready in case they decide to stop importing it or some nonsense.

With just a quick check I find 7.62 x 39 steel case ammo selling for around 20 cents per rd. with current jacketed bullet prices it's going to be hard to beat that price but it possible shooting cast lead if you want to go that route. I started out around 15 year ago loading for the X 39 in my SKS rifles to guard agents imports being cut off and they have been shortages a couple of times and you couldn't find ammo anywhere.

Back then I used Hornady FMJ, SP and V-MAX bullets that I bought in bulk for around 8 to 10 cents a bullet. Not much savings there but I had better quality ammo that I could tailor to my rifles and better bullet performance plus I didn't have to worry about shortages. When I started casting my own bullets and using different powders or lesser amounts for cast lead that gave me more rds. per pound I cut my cost down to around 10 cents per red which I can still load it at that price today.

Cast lead is pretty much all I ever shoot in my SKS rifle or any of my other firearms for that matter. My favorite powders for the SKS rifles are 2400, Reloader #7 and either IMR or H-4895. My favorite cast bullets are Lee .312" 160 gr. RF or the Lee .312" 185 gr. RN and a NOE .314" 155 gr. FN, all are of the gas check design. Those same three bullets also do double duty in all my Mosin rifles and the Lee 160 gr. I size down and shoot in my 300 Sav.

All my SKS rifle have .312" groove to groove bores but shoot .310" jacketed bullets or .313 to .314" cast lead bullets best. Personally I've never found a commercial or surplus 7.62 x 39 cartridge loaded with a .312" dia. bullet. Even if its not currently affordable to reload the X39 cartridge you can produce better quality ammo and you never have to worry about political winds.

I'm not sure I did a perfect job, but I have some .30 caliber carbine bullets. I put them in the vice to expand their girth to make sure it contacted the bottom of the grooves. Then I hammered them into the muzzle and beat them out with the brass rod (I bought for this purpose) from the breach end. The bullets for both the Mosin Nagant and the SKS both measured .310" diameter.

I'm not sure I did a perfect job, but I have some .30 caliber carbine bullets. I put them in the vice to expand their girth to make sure it contacted the bottom of the grooves. Then I hammered them into the muzzle and beat them out with the brass rod (I bought for this purpose) from the breach end. The bullets for both the Mosin Nagant and the SKS both measured .310" diameter.

Is that right from what you have seen?

Sounds like you did it right, I usually use a lead bullet, but use what you have. As to the size; It appears they are both .310, so for cast I would use a .311" or .312" sizer (Harder alloys size smaller by up to .001). On jacketed bullets anything .310 on up to .313. Midway has Lee's in .309, .311, & .314 I used an old Lyman G&H and have a ton of used dies. They used to make just about any diameter from .300 up to .327 by .001 increments. I see them used all the time! and some people don't know what they are.

Also if at Gun Shows, you can find partial boxes of gas checks, they become affordable otherwise I would stick to coated or jacketed! 3 to 7 cents each is outrageous! I'm starting to get into coated for that reason!